It is known to operate a photographic camera in such a way that the camera user can select different aspect ratios of prints to be produced from exposed image frames on the film. It is desirable to record data on the film associated with each image frame which indicates this print aspect ratio for each respective frame. This recorded data can then be read appropriately at the photoprinter to automatically set the print conditions that will produce a print with the selected aspect ratio. The data may be magnetically recorded on a magnetic layer formed on the film or optically as a latent image marks exposed on the film emulsion. In a recently proposed photographic system, the print aspect ratio data is recorded as one or more latent image blips, colloquially referred to as fat bits, along the margin of the film adjacent each exposed image frame. Such a system is illustrated in FIG. 3 which shows a film strip 80 having spaced apart pairs of perforations 81,83 which delineate regularly spaced image regions F on the film strip. Within the image regions F, a sequence of exposed image frames 82 are shown in dotted outline with the respective different print aspect ratios shown by solid lines. Frame 82H has an aspect ratio of approximately 1:2, similar to that of a high definition television image; frame 82P has an elongated panoramic aspect ratio of approximately 1:3; and frame 82L has the aspect ratio of 2:3 found in present day 35 mm film formats. In the proposed system, defined zones along the film margin, indicated by dotted outlines 84, are reserved for recording of the latent image fat bits. As illustrated in the drawing, the absence of any recorded fat bits indicates a 1:2 print aspect ratio frame 82H. A single recorded fat bit in the zone 84 indicates a panoramic print aspect ratio frame 82P; and a pair of fat bits in the zone indicates a 2.times.3 print aspect ratio frame 82L.
When using optical data recording of fat bits on film, it is desirable to use light emitting devices (LED) as opposed to, for example, incandescent devices because of the comparatively lower cost of LED devices. One difficulty with the use of LED's is that they require a minimum voltage energy source to operate, typically 1.8 v to 2.2 v. In more expensive cameras that typically use 3 v lithium batteries, this is not a problem. Lower cost cameras are common that use a single AA battery that produces 1.5 v, the currently popular single use camera being a typical example of such. There is a need, therefore, to provide an energy source to operate light emitting devices that have voltage source requirements exceeding the 1.5 v battery voltage levels typically encountered in low cost cameras.